JP7309812B2 - Printed chemical mechanical polishing pad with controlled porosity - Google Patents

Description

The present invention relates to polishing pads used in chemical mechanical polishing.

Integrated circuits are typically formed on a substrate by successively depositing conductive, semiconductive, or insulating layers on a silicon wafer. Various manufacturing processes require planarization of the layers of a substrate. For example, in certain applications, such as polishing a metal layer to form vias, plugs and lines in trenches in a pattern layer, the upper layer is planarized until the upper surface of the pattern layer is exposed. In other applications, for example, when planarizing a dielectric layer in photolithography, the upper layer is polished until the desired thickness remains above the lower layer.

Chemical-mechanical polishing (CMP) is one accepted polishing method. This method of planarization typically requires that the substrate be mounted on a carrier head. The exposed surface of the substrate is typically placed against a rotating polishing pad. A carrier head applies a controllable load to the substrate and presses the substrate against the polishing pad. A polishing liquid, such as a slurry having abrasive particles, is typically supplied to the surface of the polishing layer.

One goal of chemical-mechanical polishing processes is polishing uniformity. If different areas of the substrate are polished at different rates, too much material ("overpolishing") or too little material ("underpolishing") may be removed from some areas of the substrate. .

Conventional polishing pads include "standard" pads and fixed polishing pads. A standard pad has a polyurethane polishing layer with a durable roughened surface and may also include a compressible backing layer. In contrast, a fixed abrasive pad has abrasive particles retained in a storage medium and can be supported on a generally incompressible backing layer.

Polishing pads are typically made by molding, casting, or sintering polyurethane materials. In the case of molding, the polishing pads can be made one by one, for example by injection molding. For casting, a liquid precursor is cast, hardened into a solid, and then sliced into individual pad pieces. These pad pieces can then be machined to final thickness. A plurality of grooves can be machined into the polishing surface or can be formed as part of an injection molding process.

In addition to planarization, polishing pads can be used in finishing steps such as buffing.

The material properties of the polishing pad affect polishing. The bulk porosity of the polishing layer affects its compressibility, and the surface porosity of the polishing layer can contribute to slurry distribution. Porosity can be measured as the volume fraction of voids within a material.

Porosity in the polishing layer is typically introduced by including a material in the polishing pad that is different than the pad material. However, at the interface between the pad material and the dissimilar material, the difference in hardness of the two materials can cause secondary scratches on the substrate being polished.

In some polishing layers, air bubbles are injected into the liquid precursor to form voids. Achieving uniformity in the local distribution of air bubbles is difficult, and the local distribution of air bubbles can result in differences in hardness across different regions of the polishing layer. Variations in pad hardness can affect within-wafer uniformity of polished substrates. Conventionally, grooves are machined into the polishing layer to facilitate transport of slurry along the polishing surface of the pad. However, the profile of the grooves in the abrasive layer is limited in milling, lathing, or machining processes. Additionally, fibers of the abrasive layer material can remain on the sides of the groove after milling. These textured fibers can cause localized resistance to slurry flow.

3D printing allows better control over the distribution of pores in the polishing layer. Alternatively, or in addition, 3D printing can be used to create grooves of a specific profile and/or reduce (eg, remove) fibers in the grooves caused by conventional processing of the abrasive layer.

In one aspect, a method of manufacturing a polishing pad includes determining a desired distribution of voids to be introduced within a polymer matrix of a polishing layer of the polishing pad; generating. The control signal designates a plurality of first locations where the polymer matrix precursor is to be deposited and a plurality of second locations corresponding to the desired distribution of voids where no material is to be deposited. A 3D printer sequentially deposits multiple layers of polymer matrix corresponding to the plurality of first locations, each layer of the multiple layers of polymer matrix being deposited by ejecting a polymer matrix precursor from a nozzle. . The polymer matrix precursor is solidified to form a solidified polymer matrix having the desired distribution of voids.

Implementations may include one or more of the following features.

Determining the desired distribution of voids can include determining one or more parameters selected from the group consisting of size of the voids and spatial location of the voids within the polymer matrix.

One or more parameters can be selected to compensate for different linear velocities of the polishing pad on the rotating polishing platen.

Printing selected areas of the polishing layer can be performed to form a plurality of grooves in the upper surface of the polishing layer, the plurality of grooves including areas where the polymer matrix precursor is not deposited.

The plurality of grooves can have different depths across the top surface of the polishing layer.

A plurality of grooves may connect the voids distributed in the first pattern to form a channel network configured to carry the slurry.

Solidifying the polymer matrix precursor in situ after dispensing (dispensing) the polymer matrix precursor from the 3D printer and before the polymer matrix precursor is deposited at adjacent locations in the layer. Curing may be included.

Curing the polymer matrix precursor can include ultraviolet (UV) or infrared (IR) curing.

Polymer matrix precursors can include urethane monomers.

The solidified polymer matrix can comprise polyurethane.

A second desired distribution of voids to be introduced into the polymer matrix of the backing layer of the polishing pad can be determined.

The second desired distribution of voids in the polymer matrix of the backing layer may be different than the desired distribution of voids in the polishing layer of the polishing pad.

A second desired distribution of voids in the polymer matrix of the backing layer can have a high density of voids such that the backing layer is more compressible than the polishing layer.

The material of the polymer matrix of the polishing layer can be different from the material of the polymer matrix of the backing layer.

A second plurality of layers is sequentially deposited with a 3D printer to form a backing layer.

The abrasive layer can be printed directly onto the backing layer by a 3D printer without the use of an intermediate adhesive layer such that the abrasive layer is directly adhered to the backing layer.

The voids can have dimensions of 30-50 microns.

In another aspect, a method of making a polishing pad includes sequentially depositing a plurality of layers with a 3D printer, each layer of the plurality of polishing layers including a polishing material portion and a window portion, the polishing material comprising: The portion is deposited by discharging a polishing material precursor from a first nozzle and solidifying the polishing material precursor to form a solidified polishing material, and the window portion is deposited by discharging the window precursor from a second nozzle. It is deposited by ejecting and solidifying the window precursor to form a solidified window.

Implementations may include one or more of the following features.

By curing the abrasive material precursor and the window precursor, multiple polymer matrices having the same composition can be formed.

The abrasive material precursor may contain an opacity-inducing additive, and the window precursor may be free of such additives.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects and advantages of the invention will be apparent from the description and drawings, and from the claims.

1A is a schematic cross-sectional view of an exemplary polishing pad, 1B is a schematic cross-sectional view of another exemplary polishing pad, and 1C is a schematic cross-sectional view of yet another exemplary polishing pad. 1 is a schematic side view, partially in section, of a chemical-mechanical polishing station; FIG. 1 is a schematic cross-sectional view showing an exemplary 3D printer used to manufacture polishing pads; FIG. FIG. 4 is a schematic cross-sectional view showing a polishing layer having pores formed by 3D printing; 1 is a schematic cross-sectional view of an exemplary 3D printer with an in-situ curing light source; FIG. 4 is a schematic cross-sectional view of a groove in an exemplary polishing layer; FIG. FIG. 4 is a schematic cross-sectional view of grooves with machined fibers of an exemplary polishing pad;

The same reference numbers in the various drawings refer to the same elements.

Referring to FIGS. 1A-1C, polishing pad 18 includes polishing layer 22 . The polishing pad can be a single layer consisting of a polishing layer 22, as shown in FIG. 1A, or a multi-layer polishing pad, as shown in FIG. It can be a pad.

Polishing layer 22 may be an inert material in the polishing process. The material of the polishing layer 22 can be plastic, such as polyurethane. In some implementations, polishing layer 22 is a relatively strong, hard material. For example, the polishing layer 22 can have a hardness of about 40-80, such as 50-65, on the Shore D scale.

As shown in FIG. 1A, the abrasive layer 22 can be a layer of homogeneous composition, or as shown in FIG. 1B, the abrasive layer 22 comprises abrasive particles 28 held in a matrix 29 of a plastic material such as polyurethane. can contain Abrasive particles 28 may be harder than the material of matrix 29 . Abrasive particles 28 may be from 0.05 to 75% by weight of the abrasive layer. For example, abrasive particles 28 may be less than 1 weight percent of abrasive layer 22, such as less than 0.1 weight percent. Alternatively, abrasive particles 28 can be greater than 10% by weight of abrasive layer 22, such as greater than 50% by weight. The abrasive particle material may be a metal oxide such as ceria, alumina, silica, or combinations thereof.

In some implementations, the polishing layer includes pores, eg, small voids. The pores may be 50-100 microns wide.

Polishing layer 18 may have a thickness D1 of 80 mils or less, such as 50 mils or less, such as 25 mils or less. Because the conditioning process tends to wear away the cover layer, the thickness of polishing layer 22 may be selected to provide polishing pad 18 with a useful life of, for example, 3000 polishing and conditioning cycles.

On a microscopic scale, polishing surface 24 of polishing layer 22 may have a rough textured surface, eg, 2-4 microns rms. For example, polishing layer 22 may be subjected to a grinding or conditioning process to produce a rough textured surface. Additionally, 3D printing can provide uniform features as small as, for example, 30 microns.

While the polishing surface 24 may be rough on a microscopic scale, the polishing layer 22 may have good thickness uniformity on the macroscopic scale of the polishing pad itself (this uniformity refers to the thickness of the polishing surface 24 relative to the bottom surface of the polishing layer). refers to global variations in height and does not include any gross grooves or perforations intentionally formed in the polishing layer). For example, the thickness non-uniformity can be less than 1 mil.

Optionally, at least a portion of polishing surface 24 may include a plurality of grooves 26 formed therein for carrying slurry. Grooves 26 may be of virtually any pattern, such as concentric circles, straight lines, cross-hatching, spirals, and the like. Assuming grooves, the polishing surface 24, ie, the plateau between the grooves 26, can be about 25-90% of the total horizontal surface area of the polishing pad 22, ie. Thus, grooves 26 may occupy 10-75% of the total horizontal surface area of polishing pad 18 . The plateaus between grooves 26 may have a lateral width of about 0.1-2.5 mm.

In some implementations, grooves 26 may extend completely through polishing layer 22 , for example when backing layer 20 is present. In some implementations, grooves 26 may extend through about 20-80%, such as 40%, of the thickness of polishing layer 22 . The depth of groove 26 may be 0.25 to 1 mm. For example, in a polishing pad 18 having a polishing layer 22 that is 50 mils thick, grooves 26 can have a depth D2 of approximately 20 mils.

Backing layer 20 may be softer and more compressible than abrasive layer 22 . The backing layer 20 may have a hardness of 80 or less on the Shore A scale, such as about 60 Shore A hardness. The backing layer 20 may be thicker, thinner, or the same thickness as the polishing layer 22 .

For example, the backing layer may be an open-cell or closed-cell foam, such as polyurethane or polysilicon, with voids that cause the cells to collapse under pressure, compressing the backing layer. Suitable backing layer materials are PORON 4701-30 from Rogers, Inc. of Rogers, Connecticut, or SUBA-IV from Rohm & Haas. The hardness of the backing layer can be adjusted by selecting the layer material and porosity. Alternatively, the backing layer 20 may be formed from the same precursor and have the same porosity as the polishing layer, but have a different degree of hardening, resulting in a different hardness.

Referring now to FIG. 2, one or more substrates 14 may be polished at a polishing station 10 of a CMP apparatus. A description of a suitable polishing apparatus can be found in US Pat. No. 5,738,574, the entire invention of which is incorporated herein by reference.

Polishing station 10 may include a rotatable platen 16 having a polishing pad 18 disposed thereon. During the polishing step, a polishing liquid 30 , such as polishing slurry, may be delivered to the surface of polishing pad 18 by a slurry delivery port or coupled slurry/rinse arm 32 . Polishing fluid 30 may include abrasive particles, pH modifiers, or chemically active ingredients.

Substrate 14 is held against polishing pad 18 by carrier head 34 . The carrier head 34 is suspended from a support structure, such as a turntable, and is connected by a carrier drive shaft 36 to a carrier head rotary motor which allows the carrier head to rotate about an axis 38 . The relative movement of polishing pad 18 and substrate 14 in the presence of polishing liquid 30 causes substrate 14 to be polished.

Pad hardness and other material properties of the polishing layer affect the polishing process. Pad hardness is determined by the material used to manufacture the polishing layer, the porosity range and distribution of the polishing layer, and the degree of cure used to cure the polymer matrix precursor.

Controlling the range and distribution of porosity locally controls pad hardness. For example, it can be difficult to effectively vary the materials (having different hardnesses) used to make the polishing layer spatially across the polishing surface. Similarly, it can be difficult to control the degree of cure of the pad precursor with good resolution across the polishing layer. However, it is possible to control the pore location and density in the 3D printing process, as described below.

Generally, the porosity of polishing layer 22 is introduced by including a different material in the polishing layer than the polymer matrix precursor. In some polishing pads, porosity is introduced by including pore-containing (eg, hollow) particles in the polishing layer. For example, hollow microspheres of known size can be mixed with a liquid precursor and then cured to form the material of the polishing layer. However, the difference in hardness of the two materials at the interface between the pad material and the particles can create secondary scratches on the substrate being polished.

In some polishing layers, air bubbles are used instead of particles to create voids. This method eliminates the need to use particles made of a different material than the particles of the polishing layer to create porosity. Although it is possible to control the overall porosity, it is difficult to control the pore size and pore distribution when bubbles are used. Pore distribution and local porosity are difficult to control due to the somewhat random size and location of the cells, which can lead to differences in hardness across different regions of the polishing layer. For example, bubble diameter cannot be effectively controlled because diameter is a function of local surface tension. In addition, it is difficult to control the local distribution of air bubbles, which can lead to differences in hardness across different regions of the polishing layer, causing variations in pad hardness and affecting final wafer polishing. can affect

In some implementations, the polishing pad is manufactured with evenly distributed pores.

In some implementations, the polishing pad exhibits a greater difference in linear velocity of the polishing pad at the edges (near the circumference) of the polishing pad than at the central portion of the polishing pad due to differences in the hardness of the polishing layer. Manufactured to have distributed pores that are used to compensate. If not corrected for, this difference in polishing rate across the radius of the polishing pad can result in differential polishing of the substrate as the substrate is polished at different radial locations on the polishing layer.

In some implementations, the polishing pad is manufactured with distributed pores that compensate for other sources of non-uniformity in polishing rate due to variations in the hardness of the polishing layer.

To effectively control the hardness of the polishing layer, computer simulation can first be used to determine the desired hardness of the polishing layer at different locations of the polishing layer. The simulation produces a hardness profile for the polishing layer that can be used, for example, to compensate for differences in linear velocity of the polishing pad as it rotates. Based on the selected hardness profile, the porosity is then appropriately distributed to achieve the selected profile. The pore size, pore density and spatial distribution can be matched to the selected hardness profile.

3D printing offers a convenient and highly controllable process to obtain porosities determined by computer simulation. Referring to FIG. 3A, at least the polishing layer 22 of the polishing pad 18 shown in FIGS. 1A-1C is manufactured using a 3D printing process. 1A-1C is manufactured using a 3D printing process. For example, droplets 52 of pad precursor material can be ejected from nozzles 54 of a droplet ejection printer 55 to form layer 50 . Droplet ejection printers are similar to inkjet printers, but use a pad precursor material instead of ink. Nozzle 54 translates across support 51 (as indicated by arrow A).

In the deposited first layer 50 a the nozzle 54 can jet onto the support 51 . In the subsequently deposited layer 50b, the nozzle 54 can jet over the material 56 that has already solidified. After each layer 50 solidifies, new layers are deposited over the previously deposited layers until the three-dimensional polishing layer 22 is fully fabricated. Each layer is applied by nozzle 54 in a pattern stored in a 3D rendering computer program running on computer 60 .

Support 51 may be a rigid base or may be a flexible film, such as a layer of polytetrafluoroethylene (PTFE). If support 51 is a film, support 51 may form part of polishing pad 18 . For example, support 51 may be backing layer 20 or a layer between backing layer 20 and polishing layer 22 . Alternatively, polishing layer 22 can be eliminated from support 51 .

A desired distribution of pores can be incorporated into the polishing layer 22 by simply not depositing the pad precursor material in certain locations dictated by the desired distribution. That is, a pore can be formed at a particular location by simply not dispensing pad precursor material at that particular location.

In 3D printing, the desired deposition pattern can be specified in a CAD compatible file and then read by an electronic controller (eg, computer) controlling the printer. An electronic control signal is then sent to the printer to dispense pad precursor material only when the nozzle 54 has been translated to the position specified by the CAD conformance file. This way, there is no need to measure the actual pore size of the abrasive layer 22, and the actual location of the porosity to be incorporated into the abrasive layer 22 can be found in the instructions contained in the CAD file used to 3D print the material. and size are recorded.

FIG. 3B shows a detailed view of the pores 325 formed by 3D printing. Nozzle 54 deposits a first layer 310 made of a series of pad precursor portions 311 deposited at the resolution of the printer containing nozzle 54 . Portion 311 is shown only schematically in rectangular shape. For example, in a typical high-speed printer having a resolution of 600 dots per inch (dpi), each portion 311 (eg, each pixel) may be 30-50 microns wide.

After depositing the first layer 310 in succession, the nozzle 54 is used to deposit the second layer 320 . The second layer 320 contains voids 325 where the nozzle 54 does not deposit the polymer matrix precursor. Pores of 30-50 microns can be formed in the second layer 320 by simply not depositing material at these locations.

The layer immediately above the voided portion may have an overhang 332 just above the void 325 in the second layer 320 . Overhang 332 is held laterally by the surface tension of deposited polymer matrix precursor portion 331 , thus preventing overhang 332 from falling into void 325 . Nozzle 54 then continues to deposit polymer matrix precursor portion 333 including overhang 334 extending over void 325 . As with overhang 332 , the surface tension of deposited polymer matrix precursor portion 333 prevents overhang 332 from falling into void 325 .

The thickness of each printed layer 310-330 may be 30-50 microns. Although rectangular shaped voids are shown in FIG. 3B, in general the pores of the polishing layer may be spherical or have other geometries such as, for example, cubic or pyramidal. The minimum void size is determined by the printer resolution.

Alternatively, in pores near the polishing surface of a pad having pore surfaces that wear away during the polishing process, a fluid compatible with the polishing process (eg, water) can be deposited into the voids by, for example, a second nozzle. The pad precursor material deposited over the voids is not miscible with the fluid and is prevented from falling into the voids by the presence of the fluid. During the polishing process, if a portion of the pore surface is worn away, the fluid used during the polishing process will flow out of the pores and the pores will have the compressibility of an empty pore.

Ultraviolet (UV) or infrared (IR) curable polymers can be used as the pad precursor material to manufacture the polishing layer, eliminating the oven required when manufacturing polishing pads using injection molding. . The polishing pad manufacturing process can be moved from the vendor site and licensed directly to the customer for use at the customer site, allowing the customer to manufacture the number of pads actually required.

Solidification of the deposited pad precursor material can be accomplished by polymerization. For example, the layer of pad precursor material 50 can be a monomer, and the monomer can be polymerized in situ by UV curing. For example, a UV or IR light source 360 can be positioned fairly close to nozzle 54, as shown in FIG. 3C. In this case, in-situ curing can occur immediately after the pad precursor material is dispensed from nozzle 54 so that the deposited material solidifies when deposited at the desired location of the polishing layer. Additionally, the intensity of the UV or IR light source can be adjusted such that in-situ curing occurs to the extent that it imparts sufficient structural rigidity to the deposited pad precursor material. Alternatively, after depositing all layers 50 of pad precursor material, all layers 50 can be cured simultaneously.

In addition to using a curable pad precursor material, droplet 52 may be a polymer melt that solidifies when cooled. Alternatively, the printer creates the abrasive layer 22 by scattering a layer of powder and ejecting droplets of binder material onto the layer of powder. In this case, the powder may contain additives such as abrasive particles 22, for example.

Grooves Conventionally, grooves 26 formed in the polishing surface 24 are typically machined to carry slurry into the polishing surface 24 . However, the groove profile is limited by the milling, lathe or machining process.

By using 3D printing, it is possible to create grooves with a wide variety of cross-sectional shapes. For example, it may be possible to make grooves that are narrower at the top than at the bottom of the groove. For example, it is difficult to achieve a dovetail profile 370 groove as shown in FIG. 3D.

Fibers 380 of the pad material may remain on the sides of the groove 24 after milling, as shown in FIG. 3C. These machined fibers can cause localized resistance to slurry flow. 3D printing can reduce (or eliminate) these fibers.

Additionally, the pores can be interconnected with the grooves in a desired pattern to facilitate transport of the slurry. It is also possible to manufacture grooves of different depths in the polishing layer.

A conventional pad includes a hard cover layer (eg, abrasive layer 22) secured to a soft subpad (eg, backing layer 20) by a pressure sensitive adhesive (PSA). 3D printing can be used to create multiple layers of polishing pads in a single printing process without the use of adhesive layers, such as PSA. By printing a different precursor polymer and/or using the same pad precursor polymer but increasing the porosity of the printed structure so that the backing layer 20 is softer than the polishing layer 22. A backing layer 20 may be made. Further, backing layer 20 can be provided with a different hardness than polishing layer 22 by using different amounts of curing, such as different UV radiation intensities.

A transparent window can be embedded in the polishing layer. An optical monitoring system can direct light to and receive light from a layer of a substrate being polished through a transparent window to more accurately determine the endpoint of substrate polishing.

Instead of separately fabricating the transparent windows and then using adhesives or other techniques to secure the windows to corresponding apertures formed in the polishing layer, 3D printing deposits the transparent windows directly onto the polishing layer. It becomes possible to let For example, to dispense an optically transparent material (e.g., a transparent polymer precursor without opacity-inducing additives such as hollow microspheres) used to make transparent windows. Two nozzles are used, the first nozzle being used to dispense pad precursor material with voids at specific locations to achieve the desired porosity. The interface between the clear window material and the pad precursor is directly bonded during the printing process, no additives are required. The window can be printed as a uniform solid, for example without porosity.

3D printing methods allow tight tolerances to be achieved by printing layer by layer. Also, using one printing system (comprising printer 55 and computer 60), by simply altering the pattern stored in the 3D rendering computer program, a variety of different porosities with the desired distribution of different porosities in the polishing layer can be produced. A polishing pad can be manufactured.

In addition to tailoring the porosity distribution of polishing pads used for CMP, the methods and apparatus described herein can be used to size the porosity for shock absorption, acoustic insulation, and thermal management of parts. and porosity distribution can be controlled.

A number of implementations have been described. As such, it should be understood that various modifications can be made. For example, either the polishing pad or the carrier head, or both, can move to create relative motion between the polishing surface and the substrate. The polishing pad can be a circular or some other shaped pad. An adhesive layer can be applied to the bottom surface of the polishing pad to secure the pad to the platen, and the adhesive layer can be covered with a removable liner before placing the polishing pad on the platen. Additionally, although vertical positioning terminology is used, it should be understood that the polishing surface and substrate can be held upside down, in a vertical orientation, or in some other orientation.

Claims (12)

A method of manufacturing a polishing pad, comprising:
sequentially depositing a plurality of layers in a 3D printer to form at least a polishing layer of a polishing pad, each layer of the plurality of layers comprising a polishing material portion and a window portion, the polishing material portion comprising: is deposited by emitting a polishing material precursor from a first nozzle and solidifying the polishing material precursor to form a solidified polishing material, the window portion being deposited from a second nozzle by the window precursor and solidifying the window precursor to form a solidified transparent window, wherein the abrasive material precursor is discharged from the first nozzle and the window precursor is deposited from the second nozzle. A method comprising sequentially depositing said plurality of layers, wherein releasing a body forms an interface that directly joins said solidified transparent window and said solidified abrasive material. Solidifying the abrasive material precursor to form the solidified abrasive material comprises: after the abrasive material precursor is dispensed from the 3D printer, the abrasive material precursor is positioned adjacent the layer; 2. The method of claim 1, comprising curing the abrasive material precursor in-situ prior to being deposited. 2. The method of claim 1, wherein solidifying the abrasive material precursor to form the solidified abrasive material comprises simultaneously curing all layers of the abrasive material precursor. 2. The method of claim 1, wherein curing the abrasive material precursor comprises ultraviolet (UV) or infrared (IR) curing. 2. The method of claim 1, wherein the window portion is deposited by ejecting the window precursor and solidifying the window precursor such that the window is uniformly solid. A method of manufacturing a polishing pad, comprising:
sequentially depositing a plurality of layers with a 3D printer, each layer of the plurality of layers including an abrasive material portion and a window portion, the abrasive material portion emitting an abrasive material precursor from a first nozzle; and solidifying the abrasive material precursor to form a solidified abrasive material, wherein the window portion is deposited by discharging the window precursor from a second nozzle and solidifying the window precursor. wherein curing of the abrasive material precursor forms a first polymer matrix having a composition, and curing of the window precursor forms a second polymer matrix having the same composition. A method comprising sequentially depositing said plurality of layers, wherein a polymer matrix is formed. 7. The method of claim 6, wherein the abrasive material precursor contains an opacity-inducing additive and the window precursor does not contain the additive. 8. The method of claim 7, wherein said additive comprises hollow microspheres. 7. The method of claim 6, wherein the abrasive material precursor comprises urethane monomers. 7. The method of claim 6 , wherein the window portion is deposited by ejecting the window precursor and solidifying the window precursor such that the window is uniformly solid. A system for manufacturing a polishing pad, comprising:
a 3D printer having a first nozzle for ejecting an abrasive material precursor and a second nozzle for ejecting a window precursor;
configured to deposit a plurality of layers on the 3D printer sequentially by ejecting the abrasive material precursor from the first nozzle and the window precursor from the second nozzle; wherein each layer of said plurality of layers includes an abrasive material portion and a window portion, wherein solidified abrasive material is formed by solidifying said abrasive material precursor; and solidified transparent abrasive material is formed by solidifying said window precursor. A window is formed and the solidified transparent window and the solidified abrasive material are formed by ejecting the abrasive material precursor from the first nozzle and the window precursor from the second nozzle. a computer causing an interface to be formed directly coupling the
A system with A system for manufacturing a polishing pad, comprising:
a 3D printer having a first nozzle for ejecting an abrasive material precursor and a second nozzle for ejecting a window precursor;
configured to sequentially deposit a plurality of layers on the 3D printer by ejecting the abrasive material precursor from the first nozzle and the window precursor from the second nozzle; wherein each layer of said plurality of layers includes an abrasive material portion and a window portion, wherein solidified abrasive material is formed by solidifying said abrasive material precursor; and solidified transparent abrasive material is formed by solidifying said window precursor. Windows are formed such that curing of the abrasive material precursor forms a first polymer matrix having a composition and curing of the window precursor forms a second polymer matrix having the same composition. computer and
A system with

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